1. Field of Invention
The present invention relates to the preparation of an organic-inorganic polymer comprising boron-carbon-silicon, the polymer itself and the ceramic produced by the pyrolysis of the polymer.
2. Description of Related Art
Ceramics are prepared by pyrolysis of various organosilicon polymers. A general discussion of the history of the field is found in K. J. Wynne, et al., Annual Reviews of Materials Science (1984), Vol. 14, p. 297; R. W. Rice, American Ceramic Society Bulletin (1983), Vol. 62, p. 889; and in G. E. Legrow, et al. (1987) American Ceramic Society Bulletin, Vol 66, p. 363. More recently, M. S. Hsu, et al., in Polymer Preprint (1986), Vol. 27, #2, p. 261, disclose a number of organic silicon-boron polymer compounds that produce refractory materials upon degradation. An organo-silicon polymer containing boron may improve the properties of the polymer and the ceramic product.
It is reported by E. C. Ashby, Journal of the American Chemical Society (1959), Vol. 81, p. 4791 and by M. F. Hawthorne, Journal of Organic Chemistry (1959), Vol. 23, p. 1788, that diborane (H.sub.3 B:BH.sub.3) and a borane: amine complex react with organic olefin compounds to form saturated addition products: ##STR2##
R is an organic group in this reference. However, no polymer was synthesized from this reaction.
Amine adducts of borane are reported to be useful in the hydroborane reaction. For example, M. F. Hawthorne, Journal of the Chemical Society (1960), Vol. 82, p. 748; and H. Steinberg, et al. (Ed.) Progress in Boron Chemistry, Vol. 1, the MacMillan Company, New York, N.Y., 1964, report the complex trimethylamine-t-butylborane reacts rapidly with olefin near 50.degree. C. to produce t-butyl dialkylboron compounds or heterocyclic boron compounds.
U.S. Patents of interest include J. A. Dupont, et al., U.S. Pat. No. 3,154,520; S. R. Riccitiello, et al., U.S. Pat. No. 4,767,728; S. Yajima, et al., U.S. Pat. No. 4,152,509; and E. N. Peters, U.S. Pat. No. 4,235,987.
All references and patents cited herein are incorporated by reference in their entirety.
None of the above references disclose or suggest the polymer precursors, the polyorganoborosilicon or silicon-boron ceramic polymers of the present invention.
It is highly desirable to have polymer precursors for -Si-B-C-ceramic materials that are formed from readily available and relatively inexpensive starting materials and in high yield. Additional desirable properties include stability at room temperature for prolonged periods of time, and high yield of ceramic material upon pyrolysis. The present invention provides such useful silicon-carbon-boron ceramic materials.